Improvement in fire-escapes



2 Sheets-Sheet 1. J. S. COCHRAN.

Y FIRE-ESCAPE.

No.182,061. Patented sept.1z,1s7.e.

.n.PETERs, FHOTO-LTHCGRAPHER. WASHMGTON. D .C.

ZSheets-Sheet2- J. S.COCHRAN.

FIRE-ESCAPE.

Patented Sept. 12,v 1876.

s m5. i;

r4. PETERS, PHGTGLITHOGRAPHER 'umm PATENT OFFICE;

- JoHN seooHRAN, or New YORK, N. Y.

lMPRiovEMi-:NTJN FIRE-ESCAPES.

Specification forming part of Letters Patent No. 1282,06 l, dated September 12, 1876; application iled i August 18, 1876.

4To all whom it may concern.:

Be it known that I, JOHN STUART COOH-g RAN, of the city, county, and State of New'` York', have invented certain Improvements in 1 Fire-Escapes, of which the following is a speci- -5 tication centrifugal friction-blocks, the pressure of which upon-the surface of a surrounding drum retards the motion of the chain to keep the same within the'ilimit's of safety when persons are descending therefrom from a greateror As hitherto constructed rev less elevation. escapes of this class have' been opengto the objection that the sprocket-wheel,together with its drum and other adjuncts, have `been tilted sidewise, causing the drum to-bind in its bearings, and cause it to Workwith greatly diminished freedomand reliability.

The object of my invention is to obviate these serious drawbacks, whilerproviding a fire-escape of the class mentioned, which shall be reliable under all circumstances, and which shall retain its parts in their normal relation with each other yno matter what the strain brought upon the endless chain during the descent of one or more persons on said chain.

To this end my invention comprises, in a fire-escape, thefsprocket-wheel of which is sustained upon a pivot provided in a hanger, and arranged at the axis of the circular drum surrounding the friction-blocks actuated by said sprocket-wheel, the entire weight of the sprocket-wheel and its adjuncts, the drum, the chain, and the weight placed upon the latter being carried by the pivot aforesaid, provided in the hanger as just set forth, the hanger having its point of suspension arranged nearly or quite in the same plane with the groove of the sprocketwheel, and thereby preventing the tilting of the apparatus when in use, while the drum, being concentric with the pivots, insures the full and effective operation of the friction-blocks in permitting the movement of the chain at a proper speed, without liability either of stoppin g the same or permitting such chain to move at a too great or dangerous velocity.

The invention further comprises a novel combination of a stop with'the hanger, and with the drum surroundin g the centrifugal frictionblocks actuated from the sprocket-'wheel and chain, whereby the drum is kept lin a fixed position with reference to the hanger during the rotation of the sprocket-wheeh'the chain,

This invention relates to that class of reescapes in which'an endless chain is passed `over a sprocket-wheel, which gives rotation to and the centrifugal'friction-blocks, in order to prevent the turning of the drum with the movement of the sprocketwheel, which would of course diminish the `retardingaction of the friction-blocks during the use and operation ofthe apparatus.

Figure l is an edge view of a fire-escape, made according to "my invention. Fig. 2 is a side view of thesame. Fig. 3 is a central transverse ,sectional 'view of the same taken in the line Y Y of Fig. 4. Fig.4`is a longitudinal sectional view of the same taken in the line X Xof Fig. 3. Figs. 5 and 6 are detached views of the sprocket-wheel auditsv adjuncts, for giving-movement to* the centrifugal friction-blocks.

A is the drum, having at its center a circu-` lar opening, a, concentric with its circular inner circumference b. This drum is provided with an arm, A', which, in the axial line ot' the drum, has `a bearing, o, on the pivot B, this pivot B being provided in the frame or hanger` C, the shape of which ismore fully shown in Fig. 3. D is the sprocket-Wheel, with the usual deep groove in its periphery,

and is situated ih the space between the inner fitting into the recess b in the end of the adl jacent projection f. By this means each of the centrifugal friction-blocks F is freely pivoted in the projection f of the spider E aforesaid, the outerl surface of each friction-block `being so arranged as to come in contact with the inner circumference of the drum when the block is thrown out centrifugally by the rapid rotation of the spiderin other words, of the sprocket-wheel.

It is to be observed th at the aforesaid inner circumference of the drum A vis concentric "with the `pivot B, upon vwhich'the sprocket Wheel and its adjuncts and the drum are supported. Projecting from the bottom of the drum is a loop or staple, G, `through which passes the bolt G, extending across the lower part of the bracket C. that this bolt sustains no part ot' the drum, but it is so arranged as to prevent any rota-` tion or turning of said drum when friction in a circular direction is brought against the same by contact of' the friction-blocks, hereinbefore referred to, and hereinafter more fullyvexf plained. His the endless chain, ot'anysuita-r ble length, passed over the sprocket-Wheel D in the same manner as over the sprocket-v Wheels of other fire-escapes of the class to ,i

which my said invention relates, as hereinbefore set forth; said chain, therefore, requiring no specific description. v

It will be particularly borne in mind thati the point'g of suspension of the bracket G isil in the same plane as that in which the endlessI chain works. In the operationof the apparatus the draft ofthe chain, therefore, is coincident with the point of suspension of the drum,

sprocket-Wheel, 85e., and any ytendency to laterally tilt the drum when strain is brought.

upon the chain is eii'ectually avoided. K

In the opera-tion of the apparatus, oneside of the chain is grasped by the party or `parties descending. This turns the sprocket -wheel With greater or less velocity. A free descent of the chain grasped by the party descending is allowed up to a certainpoint, at which point the friction-blocks are thrown forcibly outward by centrifugal force, in contact with the innercircumference of the drum A, andas thel speed increases this friction increasesI in due proportion, and, retarding the descent, keeps It will be observed the velocity of such descentvvithin thelimits ffsafet'y. ".Uhiisfaction of the centrifugalblocks is 'rendered 5uniform at all *portion'sof the :revolution on the said blocks in proportion to vvthe velocity with which the sprocket-wheel,

and, consequently, the friction-blocks, is revolved b'yt'he yposition of the inner circumference of the drum concentric with the pivot B, supporting said` drum, and constituting the pivot r'arisof 1n'otion of the sprocket-Wheel and friction-blocks.

In order to protect the parts from undue 'exposure or injury fa hood, il, of s'heetfmetal, and 'formed in suitable shape, may be placed over the same, as shown in Figs. 1, 2, 3, and 4.

lt is, of' course, to be understood that when the apparatus is in vuse the `h'angerCis 'at tache'd, yat the point of suspension: g,'to 'any suitable supporti-as, for example, a bracket,

beam, orarm yprojected from a Windowor `roof of .the'buildingx i n What 'I claim as my invention is-.

l. In a-refescapafthe sprocket--Wheell-D,

sustained by the pivot B of the hanger C, havingitfs fpointof suspension fin the same plane as'the gr ")ov:efot' the*sprocket-Wheel,A in

combination with the drum and `the centrifugal friction-blocks, the inner circumference of the/drum beingconcen'tricf-With the pivot B, `all substantiallyfas and-for therpurpose'herein set forth. y. y l2. Thestaple or 1stop vGrou 'the drum, and the bolt attached tog-the 'hangen-said parts constituting *'avs'tvop which prevents the turning-:of `the drum within the 'lhangensubstahtially as I'and ffor 'the purpose herein set forth'.

v JOHN S. COCHRAN.

Witnesses: Y.

EDWARD A'HOLL-Y,

H. WELLs,-J`r. 

